The invention relates to a vane for a vane cell device comprising a stator and a rotor rotatably arranged in the stator with a plurality of guide grooves in each of which a vane can be movably mounted along a direction of movement. The invention also relates to a vane cell device.
Such vane cell devices can be liquid-conveying vane cell pumps, or liquid-driven vane cell motors. Also, vane cell devices in the form of vane cell measuring devices are known in which the amount of fluid flowing through the vane cell measuring device can be determined by counting the number of rotations of the rotor taking into account the fluid volume throughput per rotation. They possess, in a manner known per se, a stator in which a rotor is rotatably arranged. The stator possesses at least one inlet opening and at least one outlet opening for the fluid. Furthermore with such vane cell devices, vanes (also termed “slide valves”) are arranged in suitable guide grooves of the rotor and move back and forth radially, or primarily radially, in the guide grooves of the rotor while the vane cell device is operating. The rotor, in conjunction with the vanes, separates the low-pressure chamber from the high-pressure chamber.
It is known to fill a gap with conveying or driving fluid through corresponding channels in the rotor or vane, said gap arising during the radial movement of the vanes between the base of the guide grooves and the radially inward end of the vanes when the vanes partially move out of the drive groove. This is necessary to prevent negative pressure from arising in the arising gap which would inhibit the movement of the vane. When the vane moves back into the guide groove in a radial direction, the fluid must be able to flow out of the gap between the groove base and the vane through the fluid channels without unnecessarily impairing the vane movement.
The fluid channels formed in the rotor can be advantageously designed as fluid channels with a large cross-section. This design is however comparably expensive. The fluid channels formed in the vane can only be realized as fluid channels with a small cross-section for design reasons. This design is therefore less expensive. It is known to limit the fluid channels with ribs. The ribs must possess a sufficient thickness in order to limit the wear of the guide grooves. This also leads to the reduction of the cross-section of the fluid channels.
The small cross-section of the fluid channels formed in the vanes can generate negative pressure in the gaps between the groove bases and the vanes that increases strongly as the rotational speed of the rotor increases. This negative pressure is reinforced by rotational centrifugal force. Starting at a threshold rotational speed of the rotor, this negative pressure can undesirably inhibit the vane movement out of the rotor, or cause the liquid in the gaps between the groove bases and the vanes to outgas or evaporate which leads to an additional functional restriction and undesired noise.